Pharmacy generally began with the compounding of medicines which entailed the actual mixing and preparing of medications. Heretofore, pharmacy has been, to a great extent, a profession of dispensing, that is, the pouring, counting, and labeling of a prescription, and subsequently transferring the dispensed medication to the patient. Because of the repetitiveness of many of the pharmacists tasks, automation of these tasks has been desirable.
Some attempts have been made to automate the pharmacy environment. Different exemplary approaches are shown in U.S. Pat. No. 5,337,919 to Spaulding et al. and U.S. Pat. Nos. 6,006,946; 6,036,812 and 6,176,392 to Williams et al. The Williams system conveys a bin with tablets to a counter and a vial to the counter. The counter dispenses tablets to the vial. Once the tablets have been dispensed, the system returns the bin to its original location and conveys the vial to an output device. Tablets may be counted and dispensed with any number of counting devices. Drawbacks to these systems typically include the relatively low speed at which prescriptions are filled and the absence in these systems of securing a cap (i.e., a lid) on the container after it is filled.
One additional automated system for dispensing pharmaceuticals is described in some detail in U.S. Pat. No. 6,971,541 to Williams et al. (hereinafter Williams '541). This system has the capacity to select an appropriate vial, label the vial, fill the vial with a desired quantity of a selected pharmaceutical tablet, apply a cap to the filled vial, and convey the labeled, filled, capped vial to an offloading station for retrieval.
Although this particular system can provide automated pharmaceutical dispensing, certain of the operations may be improved. For example, the device that dispenses caps includes a hopper with a circumferential groove or gap at its lower end that surrounds a rotatable central circular drum. The groove has a depth that is larger than the diameter of a cap and a width that is approximately the width of the cap. A circumferential rim juts radially inwardly from the wall of the hopper above the groove and drum. The sizes and configurations of the groove, drum and protrusion are such that a cap (which is a relatively flat, open-ended cylinder) can enter the groove from above only when the cap is oriented so that the open end of the cap faces the drum. This occurs because the open end of the cap can receive an arcuate portion of the edge of the drum, thereby allowing the cap to be positioned slightly closer to the wall (and, therefore, able to slide into the groove) than a cap oriented with the closed end facing the drum, which cannot pass between the drum and the rim in this manner. The floor of the hopper has an opening through which caps, once in the groove, can pass one at a time to a capping station.
Caps are dispensed by filling the bin with caps and rotating the drum. As the drum rotates, each cap tumbles until it eventually reaches the desired orientation and slides into the groove. As the drum continues to rotate, the cap eventually reaches the opening, at which point it passes through the opening and can pass to the capping station.
One issue that can occur with the Williams '541 system is the dispensing of multiple caps at once. In some circumstances, caps may have edge features (often associated with child-resistant caps) that can tangle or otherwise interlock at their edges, particularly when they are in an edge-stacked relationship while positioned in the groove. When this occurs, two interlocked caps may be dispensed at once. It would be desirable to address this behavior.